1. Field of the Invention
The present invention relates to an electric blind apparatus. More specifically, it relates to an electric blind apparatus which can raise/lower a blind by an electric motor while opening/closing vanes of the blind.
2. Description of the Prior Art
Various types of electrified automatic blinds have recently been proposed for installation in an office, a board room, a store and the like. Such convenient automatic blinds are increasingly coming into wide use, to be further spread for domestic use in the near future.
Japanese Utility Model Publication Gazette No. 17676/1981 discloses an example of such an automatic blind. This automatic blind includes a switch for changing the direction of rotation of a DC motor, so that the DC motor is normally or reversely rotated by the switch to raise/lower the blind by its driving force. The DC motor is stopped when the blind reaches an upper or lower limit position. However, this automatic blind is merely adapted to raise/lower the blind, and a period of turn-on of the motor is merely controlled according to an output of an oscillation circuit to regulate vanes thereof at an arbitrary open/close angle.